A network appliance is often provided with a physical user interface port. A legitimate user can hook up to the port, and can configure and monitor operation of the network appliance through the port. Unfortunately, such a port can often also often be attacked and exploited by illegitimate users. Most attacks on such user interface ports are attacks on an application layer front end user interface process. Specially designed communications are sent to the front end user interface process through the provided user interface network port. These communications cause the front end process to crash or to become unstable in some way such that the user interface front end process is made to write a rogue file, where the file contains rogue executable code. The rogue executable code is then somehow made to be executed. There are many different ways to exploit different vulnerabilities so as to cause these actions to occur, but attacks generally involve causing a file of code to be written and then executed. Even though providing a user interface port presents exploitable vulnerabilities to hackers, it is nevertheless desired to provide such a port for use by legitimate users. Ways of securing the user interface port against attacks by illicit users are sought.